EP0653343B1 - Control device for steering of the rear wheels of a trailer - Google Patents

Description

The present invention relates to an installation for controlling the rear wheels of a trailer.

The invention relates to trailers with a long length and intended, more particularly, for the transport of bulky machines which cannot be moved on the roads.

The invention applies, more particularly, to trailers which, at a front end of a platform, are provided with a drawbar on which a drawbar is articulated intended to be fixed to the lifting arms of a tractor, while the rear end of said platform comprises an articulated frame supporting the wheels and with interposition of jacks so that the wheels can tilt vertically so that the platform can be lowered to the ground to loading a transport machine, while after loading it can be lifted for transport.

Such a trailer has the disadvantage that it is difficult to maneuver in small paths and that it cannot turn in sharp curves.

One of the aims of the present invention is to provide a control installation for orienting the rear wheels at the same time as the tractor is turning in order to facilitate maneuvers.

The installation according to the invention is aimed at controlling the orientation of the rear wheels of a trailer intended for transporting machines and, more particularly, agricultural machinery, said trailer having a platform, one front end of which is secured to a drawbar on which a drawbar is articulated intended to be connected to the lift bars of a tractor, while the rear end is supported by two wheels mounted on orientable yokes integral with the axes supported by a frame and connected by a coupling bar, said frame being mounted articulated at the rear end of the platform with interposition of jacks so that the platform shape can be lowered to the ground for loading, then after loading, raised for transport, said installation being characterized in that the drawbar has a vertical axis on which is mounted rotating a sleeve radially integral, on the one hand, d '' a bar connected by a kinematic link to a control member of a jack inserted between the coupling bar and the frame and connected to a dist ributor, said control member comprising a contactor connected by a kinematic link to one of the axes of orientation of the wheels and comprising a button capable of occupying a first control position for closing an electrical control circuit of the distributor for generate the elongation of the jack, a second position for controlling the shortening of the jack and a neutral position in which said electrical circuits are open, said kinematic link being connected to pushers for controlling the button as a function of the angular position of the radial bar , means being provided for annihilating the means for controlling the orientation of the wheels and maintaining a neutral position in which the trailer travels in a straight line.

Thanks to this arrangement, a modification of the angular function of the drawbar automatically generates the orientation of the rear wheels of the trailer in the same direction.

According to a constructive characteristic, the sleeve comprises a rod, elastic means for tending to maintain the rod in an equilibrium position parallel to the axis of the drawbar, the drawbar being provided with catches intended to cooperate with the rod. so as to tilt it in one direction or the other in correspondence with the orientation of said drawbar.

So that the system cannot lock up and cannot be damaged in tight turns, the cleats are pivoted against the action of elastic means.

When the trailer is moved on roads, it may not be desirable for the system to work; for this purpose, the rod is of adjustable length. So we can move the rod away from the cleats and the system is put to rest.

According to a constructive detail, the rod comprises a sliding mounted bushing and terminated by a head in the form of a truncated cone cooperating with the cleats.

According to yet another constructive detail, the tension springs are inserted between lugs secured to the sleeve and lugs secured to the sleeve, said sleeve being connected by a cable to a lever movable along a notched sector.

According to another constructive characteristic, the sleeve is integral with a median intermediate point of a plate whose ends are connected by springs to a fixed point of the drawbar so as to maintain the rod in an equilibrium position parallel to the axis of the drawbar.

Finally, according to a characteristic of detail, the radial bar is connected by a rod to a plate pivotally mounted freely on an axis connected to one of the yokes of the orientation of the wheels and on which the contactor is fixed, on said axis being mounted, freely rotating, two sleeves, one of which is integral with an arm and the other of a second arm, the arms being arranged on either side of the contactor and each supporting a push button cooperating with the button, elastic means tending to bring the arms closer to each other and the plate comprising two stops intended to cooperate with one arm, the other with the other, so that when the plate is angularly displaced, the 'one of the arms moves away, while the push-button of the other arm, by cooperating with the button, ensures the closing of the corresponding electrical circuit of the actuator control until the switch button, driven by the yoke , come and meet the push button e the other arm to return the button to the neutral position.

According to an alternative embodiment, the radial bar is connected to the plate by a flexible link, the latter being pivotally mounted against the action of a return spring.

According to another embodiment, in order to prevent the wheels of the trailer, when traveling on the road, from being able to move angularly, the frame comprises a cylinder for locking the wheels in the neutral position.

According to a detail characteristic, the locking cylinder is a single-acting cylinder comprising a return spring tending to bring it into the locked position and it is connected to the distributor on a bypass of the supply circuit of the actuator for controlling the orientation of the wheels and an electric control circuit is provided comprising an inverter for cutting the supply of the plate contactor so that, when the wheels occupy the neutral position, the locking cylinder not being supplied, it automatically occupies the locked position.

According to yet another characteristic of detail, one of the yokes of the wheels has a notch, while the locking cylinder is provided with a corner intended to be inserted in the notch.

Finally, according to a last characteristic, between the plate and one of the yokes of the orientation of the wheels, on the kinematic link, is inserted a second plate rotating on a fixed axis on which is fixed a contactor provided with a button, the second plate comprising two pushers cooperating with the button and capable, one of being moved away from the button when the second plate is pivoted in one direction and the other of said button when the second plate is pivoting in the other direction , said contactor being connected to circuits for controlling the distributor to bring the wheels back to neutral position, in this position the contactor cutting the control circuits so that the locking jack, under the action of its return spring, comes to occupy the locked position.

• Figure 1 est une vue en plan montrant une installation de commande de l'orientation des roues arrières d'une remorque.
• Figure 2 est une vue en plan montrant les roues orientées de la remorque de la figure 1.
• Figure 3 est une vue en plan à plus grande échelle d'un détail.
• Figure 4 montre le fonctionnement de la partie de la figure 3 dans un virage.
• Figure 5 montre en plan le détail de la figure 3 dans une position d'arrêt.
• Figure 6 est une vue en plan correspondant à la figure 5, le tracteur étant dans la position de virage.
• Figure 7 est une vue en perspective du dispositif de commande du vérin.
• Figure 8 est une vue en plan, à plus grande échelle, du dispositif de commande du vérin.
• Figure 9 montre le dispositif de commande du vérin dans une position au début d'un virage.
• Figure 10 montre le dispositif de commande du vérin, les roues étant braquées.
• Figure 11 montre schématiquement, en plan , une variante de réalisation de l'invention.
• Figure 12 est une vue, en plan, à plus grande échelle d'un détail, les roues étant en position neutre.
• Figure 13 est une vue correspondant à la figure 12, les roues étant braquées.

The invention will now be described in more detail with reference to particular embodiments given by way of example only and shown in the accompanying drawings, in which:

• Figure 1 is a plan view showing an installation for controlling the orientation of the rear wheels of a trailer.
• Figure 2 is a plan view showing the steered wheels of the trailer of Figure 1.
• Figure 3 is an enlarged plan view of a detail.
• Figure 4 shows the operation of the part of Figure 3 in a turn.
• Figure 5 shows in plan the detail of Figure 3 in a stopped position.
• Figure 6 is a plan view corresponding to Figure 5, the tractor being in the turning position.
• Figure 7 is a perspective view of the actuator control device.
• Figure 8 is a plan view, on a larger scale, of the actuator control device.
• Figure 9 shows the cylinder control device in a position at the start of a turn.
• Figure 10 shows the actuator control device, the wheels being turned.
• Figure 11 shows schematically, in plan, an alternative embodiment of the invention.
• Figure 12 is a plan view, on a larger scale of a detail, the wheels being in neutral position.
• Figure 13 is a view corresponding to Figure 12, the wheels being turned.

In FIG. 1, a tractor 1 is shown comprising lifting bars 2 on which is mounted a drawbar 3.

The drawbar 3 is secured to a support 4 having a vertical axis 5 on which is articulated a drawbar 6 of a trailer 7 constituted by a platform 8 whose rear end is connected to a supported frame 9 by two wheels 10.

The frame 9 is hingedly connected to the platform 8 with interposition of jacks 11 so that said platform can be lowered to rest on the ground in order to receive machines such as agricultural machines, then after loading, be raised so to allow the transportation of said gear.

Each wheel 10 turns madly on an axis 14 which is integral with a yoke 15 wedged on a vertical axis 16 guided on a frame 9, said yokes being connected by a coupling bar 17 so that said wheels can be oriented simultaneously and kept parallel.

On the drawbar 6 is erected a vertical axis 20 on which is mounted a sleeve 25 which is integral, on the one hand, with a radial bar 21 and, on the other hand, with a plate 22.

Between the plate 22 and a bar 23 are inserted springs 24 which tend to bring the plate 22 back into an equilibrium position in which it extends perpendicular to the drawbar 6.

The sleeve 25 is also integral with a rod 26, which in the equilibrium position extends coaxially with the drawbar 6 and on which a bushing 28 is slidably mounted.

The socket 28 is provided with two lugs 29 on which the ends of the tension springs 31 are hung, the other ends of which are attached to lugs 30 integral with the sleeve 25.

The socket 28 is terminated by a frustoconical head 33 which is integral with one of the ends of a cable 34, the other end of which is fixed to one end 36 of a lever 37 articulated on an axis 38 and capable of being blocked on a toothed sector 39.

Thus, the socket 28 can occupy an active position in which it is distant from the sleeve 25 and an inactive position in which it abuts against said sleeve 25.

The support 4 comprises two tabs 41, 41 a which are pivotally mounted on pins 42 and are normally kept applied against stops 43 by springs 44.

In the active position of the sleeve 28, the tabs cooperate with the truncated cone 33 (see Figures 3 and 4).

The bar 21 comprises, in the vicinity of its free end, an elongated lumen 47 in which slides one end of a rod 48 whose other end is connected, articulated by an axis 49 to a plate 50 (see Figures 7 to 10) .

The plate 50 turns freely on one of the axes 16, on said axis being fixed an electrical contactor 51 comprising a button 52 capable of oscillating in two opposite directions to close two electrical circuits, and of occupying a neutral position in which the two circuits are open.

On the axis 16 is mounted a first sleeve 54 secured to an arm 55 carrying at its free end a pusher 56. The stud 56 has a thread on which two nuts 57 are screwed making it possible to adjust the position of the pusher 56.

A rod 59 is also provided, which is screwed into an internal thread of the arm 55 and onto which a nut 60 and a lock nut 61 are screwed to perfect the adjustment of the pusher 56.

On the plate 50 a stop 63 is erected intended to cooperate with the arm 55.

On the axis 16 is mounted a second sleeve 65 secured to an arm 66, the free end of which comprises a pusher 67 having a thread and passing through a hole in the arm 66, the thread receiving fixing nuts 68 and 69.

The arm 66 has a screw 71 screwed into a corresponding thread with a nut 72 and a lock nut 73. The screw 71 is intended to perfect the adjustment of the pusher 67.

The arms 55 and 66 are respectively secured to bars 74 and 75 which are connected by a tension spring 76.

On the plate 50 stands a stop 77 intended to cooperate with the arm 66.

On a pivot 85 on which one of the ends of the coupling bar 17 is articulated on one of the yokes 15 is articulated the free end of the rod 84 of a jack 83 whose body is articulated on an axis 86 of the frame 9.

The jack 83 is a double-acting jack and is connected by lines 81 and 82 to a distributor 80 carried by the rear end of the platform 8.

The contactor 51 controls the distributor 80 so as to control the extension of the jack when the tractor turns to the left, or, on the contrary, the shortening of the latter, when the tractor turns to the right.

The operation is as follows:

The sleeve 28 being kept apart from the sleeve 25 against the action of the springs 31, by the cable 34 (see Figures 1 and 3), the installation is operational.

If the tractor 1 turns to the left (see Figures 2 and 4), the drawbar 3 pivots on the axis 5 and the head 33 comes to meet the cleat 41 which pushes the bush 28 in the direction of the arrow f (see FIGS. 2 and 4), the sleeve 25 then pivots against the action of the springs 24 so that the radial bar 21 pivots in the direction of the arrow g, the rod 48 making turn the plate 50.

During the rotation of the plate 50, for example in the direction of the arrow j (see FIG. 9), the stop 77, by cooperating with the arm 66, drives the latter against the action of the spring 76 so that the push-button 56 switches the button 52 which controls the distributor 80; the latter via line 81, sends pressurized oil into the jack 83 controlling the shortening thereof. Thus, the yoke 15 pivots by driving the axis 16. During this pivoting, the contactor 51 which is integral with the axis 16 pivots with the latter until the button 52 meets the pusher 67 which, by abutting against the latter, opens the electrical circuit (see Figure 10). Thus the wheels 10 are oriented in the direction corresponding to the turn.

It is understood that if the rod 48 is actuated in the opposite direction the arm 55, pushed by the stop 63, moves away from the contactor 51 and that the pusher 67 pushes the button 52 closing the electrical circuit controlling the distributor 80 for elongation of cylinder 83.

When the tractor 1 and the trailer 7 move on a long road, it is desirable that the installation does not work because the pivoting of the wheels 10 on large curves could risk shifting the trailer. As seen in Figures 5 and 6 to block the installation, simply act on the lever 37 to relax the cable 34, the sleeve 28, with the action of the springs 31, slides on the rod 26 so that the head 33 moves away from the cleats 41, 41 a . So even when cornering (see Figure 6) said head 33 can no longer cooperate with the tabs 41, 41 a so that the sleeve 25 which is held in its equilibrium position by the springs 24 does not pivot.

Figures 11 to 13 show an alternative embodiment of the invention.

In FIG. 11, a tractor 100 is shown at the rear of which is drawn the drawbar 106 of a trailer 107 consisting of a platform whose rear end is connected by jacks 110 to a frame 108 comprising two wheels 109.

This assembly is of the same type as that described in the previous figures and will not be explained here in detail.

One of the wheels 109 is carried by a yoke 112 articulated on a vertical axis 115 of the frame 108, while the other wheel 109 is carried by a yoke 113 articulated on a vertical axis 116 of the frame 108, the yokes being connected by a coupling rod 114.

On the drawbar 106 is erected a vertical axis 118 on which is engaged a sleeve 119 secured to a radial bar 120 which is connected by a cable 121 to the tractor 100 so that, when the latter rotates in one direction, the bar turns in the same direction.

The radial bar 120 is secured at its free end to one of the ends of a link 124, the other end of which is fixed to a plate 125.

The plate 125 is articulated on an axis 126 on which is engaged a torsion spring tending to rotate it in the direction of the arrow f (see FIG. 13).

The plate 125 is of the same type as the plate 50 and operates in the same way. In FIGS. 12 and 13, the various references used to designate the corresponding parts of the plate 50 but assigned the letter "a" have been reported.

On the frame 108 is articulated the body of a jack 130 whose piston rod 131 is connected to the yoke 113. The jack 130 is a double-acting jack and is connected by conduits 132 and 133 to a distributor 135 to which ends a line 137 for supplying oil under pressure and comprising a line for returning 138 to a tank.

The length of the link 124 is such that, when the tractor 100 moves in a straight line, the plate 125 occupies an angular position in which the wheels 109 are held in a neutral position so that the trailer moves in a straight line.

The axis 126 is integral with a radial arm 140 which, by a link 141, is connected to a second plate 142 itself connected by a link 143 to the yoke 112.

The plate 142 is articulated on an axis 145 on which is fixed a contactor 146 provided with a button 147 capable of being actuated by two pushers 148 and 149.

The plate 142 is of the same type as the plate 50 and will not be described in detail. However, unlike at axis 126, axis 145 is fixed so that the contactor 146 has no angular displacement.

The contactors 51a and 146 are inserted on circuits with the interposition of an inverter 150 so that when the contactor 51a is energized, the contactor 146 is not supplied and vice versa.

A locking cylinder 151 is provided for locking the wheels 109 in a neutral position in which the trailer travels in a straight line.

The cylinder 151 is a single-acting cylinder and has a return spring tending to bring it into the elongated locking position. It is connected by a line 153 to a bypass of the line 137 for supplying pressurized oil.

The free end of the piston rod 154 of the jack 151 is terminated by a wedge 155 intended to be inserted in a notch 156.

When the tractor turns in one direction and the link 124 is pulled, the plate 125 pivots in the direction of the arrow j (see FIG. 13), the pusher 56a pushing the button 52a to then close the control circuit so that the cylinder 130 is supplied by line 132 in order to control the shortening of cylinder 130 and thus the wheels 109 pivot in the direction corresponding to the direction of the tractor.

On the contrary, if the cable 124 is released the tractor, turning in the opposite direction, the plate 125, under the action of the torsion spring, pivots in the opposite direction at arrow j, the pusher 56a moves away from the button 52a and the pusher 67a, by cooperating with said button 52a, closes the circuit controlling the supply of the jack 130 by the line 133.

As the wheels 109 pivot on the axes 115 and 116, the axis 126 driven by the rods 141 and 143 pivots thus bringing the contactor 51a to a position in which the two pushers 66a and 56a bring the button 52a towards a neutral position, the wheels 109 remaining in the angular position thus obtained until the plate 125 is angularly moved either by pulling the link 124 or, on the contrary, loosening it.

During these various angular movements of the wheels 109, the circuit of the contactor 146 remains open.

If one acts on the inverter 150 (see FIG. 12), all of the control circuits of the contactor 52a are open, while the contactor 146, by means of the button 147, controlled either by the push-button 148, or by the pusher 149 according to the angular position of the plate controls the distributor 134 in order to bring the wheel 109 back to a neutral position in which the trailer is moved in a straight line.

When this neutral position is reached, the two pushers 148 and 149 abut against the button 147 which generates the opening of the actuator control circuit 130 and since there is no more pressure in the control 137, the pipe 153 does not no longer receives the oil under pressure so that the spring of the locking cylinder pushes the piston rod 154 towards the locking position, the wedge 155 being inserted in the notch 156. Thus, the wheels 109 are kept locked in the neutral position.

Of course, the invention is not limited to the embodiments which have just been described and shown. Many modifications of detail can be made without departing from the scope of the invention as defined in the claims which follow.

Claims (13)

1. A control installation for steering the rear wheels (10, 109) of a trailer (7, 107) intended for the transport of machines and, more particularly, agricultural machines, the said trailer (7, 107) having a platform, one front end of which is integral with a drawbar (6, 106) on which a hitch (3, 102) is articulated, which is intended to be connected to lifting rods (2, 101) of a tractor (1, 100), whereas the rear end is supported by two wheels (10, 109) mounted on directable fork joints integral with shafts (16, 115, 116) supported by a supporting structure (9, 108) and connected by a connecting bar (17, 114), the said supporting structure (9, 108) being mounted articulated at the rear end of the platform with the interposition of cylinders (11, 110) so that the platform can be lowered to the ground for loading, then after loading raised for transport, the said installation being characterised in that the drawbar (6, 106) comprises a vertical shaft (20, 118) on which is rotatingly mounted a sleeve (25, 119) integral radially with a radial bar (21, 120) connected by a kinematic connection (48, 124) to a control member of a cylinder (83, 130) inserted between the connecting bar (17, 114) and the supporting structure (9, 108) and connected to a distributor (80, 134), the said control member comprising a contactor (51, 51a) connected by a kinematic connection to one of the shafts (16, 115) for steering the wheels (10, 105) and comprising a knob (52, 52a) capable of occupying a first position controlling the closing of an electric circuit controlling the distributor (80, 134) to bring about the lengthening of the cylinder (83, 130), a second position controlling the shortening of the cylinder (83, 130) and a neutral position in which the said electric circuits are open, the said kinematic connection (48) being connected to thrustors (56, 67) for controlling the knob (52) as a function of the angular position of the radial bar (21), means being provided to overcome the means for controlling the steering of the wheels (10, 109) and to maintain a neutral position in which the trailer moves in a straight line.
2. A control installation for steering the rear wheels, according to Claim 1,
   characterised in that the sleeve (25) comprises a rod (26), resilient means (24) for tending to keep the rod (26) in a position of equilibrium parallel to the axis of the drawbar (6), the hitch (3) being provided with drivers (41, 41a) intended to cooperate with the rod (26) so as to make it swing in one direction or the other corresponding to the orientation of the said hitch (3).
3. A control installation for steering the rear wheels, according to Claims 1 and 2,
   characterised in that the drivers (41, 41a) are mounted swinging against the action of the resilient means (44).
4. A control installation for steering the rear wheels, according to Claims 1 and 2,
   characterised in that the rod (26) is of an adjustable length.
5. A control installation for steering the rear wheels, according to Claim 4,
   characterised in that the rod (26) comprises a bushing (28) slidingly mounted and ending in a head in the shape of a truncated cone (43) cooperating with the drivers (41, 41a).
6. A control installation for steering the rear wheels, according to Claims 4 and 5,
   characterised in that the draw springs (31) are inserted between lugs (29) integral with the bushing (28) and lugs integral with the sleeve (25), the said bushing being connected by a cable (34) to a lever (37) movable along a an indexed sector (39).
7. A control installation for steering the rear wheels, according to Claims 1 and 2,
   characterised in that the sleeve (25) is integral with a median intermediate point of a plate (22), the ends of which are connected by springs (24) to a fixed point of the drawbar (6) so as to keep the rod (26) in a position of equilibrium parallel to the axis of the drawbar (6).
8. A control installation for steering the rear wheels, according to Claim 1,
   characterised in that the radial bar (21) is connected by a rod (48) to a plate (50) mounted freely pivoting on a shaft (16) connected to one of the fork joints for the steering of the wheels and on which is fixed the contactor (51), on the said shaft two sleeves (54, 55) being freely rotatingly mounted, the one of which is integral with an arm (55) and the other with a second arm (66), the arms being disposed on either side of the contactor (51) and each supporting a thrustor cooperating with the knob (52), resilient means tending to bring the arms closer together and the plate (50) comprising two stops (63, 77) intended to cooperate one with one arm and the other with the other arm, in such a manner that, when the plate (50) is displaced angularly, one of the arms moves away, whereas the thrustor of the other arm, by cooperating with the knob (52), ensures the closing of the corresponding electric circuit controlling the cylinder (83) until the knob (52) of the contactor, driven by the fork joint, comes upon the thrustor of the other arm to bring the knob back into the neutral position.
9. A control installation for steering the rear wheels, according to Claim 8,
   characterised in that the radial bar (120) is connected to the plate (125) by a flexible link (124), this being mounted pivoting against the action of a return spring.
10. A control installation for steering the rear wheels, according to Claims 8 and 9,
    characterised in that the supporting structure (108) comprises a cylinder (151) for locking the wheels (109) in the neutral position.
11. A control installation for steering the rear wheels, according to Claims 8, 9 and 10,
    characterised in that the locking cylinder is a simple-action cylinder comprising a return spring tending to bring it into the locked position and it is connected to the distributor (134) on a branch conduit supplying the cylinder (130) controlling the steering of the wheels (109) and an electric control circuit is provided which comprises an inverter (150) to cut off the supply to the contactor (81a) of the plate (125), so that when the wheels occupy the neutral position, when the locking cylinder is not supplied, it automatically occupies the locked position.
12. A control installation for steering the rear wheels, according to Claim 11,
    characterised in that one of the fork joints (112) of the wheels (109) comprises a notch (156), whereas the locking cylinder (151) is provided with a wedge (155) intended to be inserted into the notch (156).
13. A control installation for steering the rear wheels, according to Claim 11,
    characterised in that between the plate (125) and one of the fork joints (112) for steering the wheels (109), on the kinematic connection (141, 143), is inserted a second plate (142) rotating on a fixed shaft (145) on which a contactor (146) provided with a knob (147) is locked, the second plate (142) comprising two thrustors (148, 149) cooperating with the knob (147) and the one being capable of being moved away from the knob (147) during the pivoting of the second plate in one direction, and the other from the said knob (147) during the pivoting of the said second plate in the other direction, the said contactor (146) being connected to circuits in order to control the distributor to bring the wheels back into the neutral position, in this position the contactor cutting off the control circuits with the result that the locking cylinder (151), under the action of its return spring, comes to occupy the locked position.

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